Nutrient and bulk density characteristics of soil profiles in six land use systems along topo-sequences in inland valley watersheds of Ashanti region,Ghana     

Ebenezer Annan-Afful  Noriko Iwashima  Ernest Otoo  Kwame Osafredu Asubonteng  Daisuke Kubota  Akira Kamidohzono 《Soil Science and Plant Nutrition》2013,59(5):649-664

The bulk density and nutrient distribution in soil profiles as affected by various land use systems were studied. Mean bulk densities of the various soil profiles, 0-20, 20-40, and 4060 cm in the selected five land use systems along the upland / lowland topo-sequences were, 1.26, 1.73, and 1.44 Mg m^-3 for the primary forest (PF) plot in the upland area, 1.13, 1.51, and 1.50 Mg m^-3 for the cacao farm (CP) plot, 1.16, 1.63, and 1.26 Mg m^-3 for the mixed cropping (MC) plot, 1.39, 1.61, and 1.50 Mg m-a for the fallow (Fallow) plot, all three land use systems being in the upland / fringe areas, and 1.46, 1.72, and 1.60 Mg m^-3 for the lowland traditional rice farming (TR) plot, respectively. The very high bulk density of the second layer, especially in the PF plot, may be related to the hardening of the iron / quartz stone layer due to prolonged dry conditions, which may affect plant growth and hydrological cycles in the benchmark inland valley watersheds. The TC contents of the topsoil samples were 43, 32, 24, 26, 18, and 15 g kgm^-1 for the PF, CP, Fallow, MC, TR, and sawah (Sawah) plots, respectively. The C / N ratios of the topsoil samples were 10, 10, 9.8, 9.1, 8.8, and 8.8 for the CP, Fallow, MC, Sawah, TR, and PF plots, respectively, displaying a higher natural fertility, especially for the N supply in the PF plot in the upland area. The available phosphorus levels were low even for the topsoil samples, 1.8 to 3.4 mg kg^-1 for the upland soils while the lowland TR and Sawah plots recorded values of 4.4 and 4.9 mg kg^-1, respectively. The contents of exchangeable K, 0.1-0.4 cmole kg^-1, of the topsoil samples were in the range of those of normal inland valley soils in West Africa. In contrast to the content of available P, although the MC plot showed a depletion, the PF, Fallow, and CP plots showed a replenishment of available K through biological nutrient cycling. The levels of exchangeable Ca and Mg as well as eCEC, were also relatively high compared to those of mean inland valley soils in West Africa. The major component of eCEC was Ex. Ca. The levels of Ex. Ca in the topsoil samples were 11.1, 9.1, 7.8, 4.7, 5.1, and 3.9 cmol_c kg^-1 for the PF, CP, Fallow, MC, TR, and Sawah plots, respectively. The distinctive feature of Ex. Mg was its large distribution in the upper soil profiles in the CP plot, indicating that in the cacao farms, Ex. Mg was enriched, probably due to the high level of Mg in the leaf litter. The lowland soils, normally, should have been enriched in exchangeable bases such as Ca, K, and Mg, leading to a higher eCEC value and higher general fertility through the process of geological fertilization, Le., nutrient flows from upland to lowland areas, as in the case of lowland sawah in monsoon Asia. At the benchmark sites, however, the effects of the geological fertilization process were not evident. This is one of the most important characteristics of West African inland valley watersheds.  相似文献   

The Use of Bacillus Licheniformis HA1 To Accelerate Composting of Organic Wastes     

Kiyohiko Nakasaki  Nobuyuki Uehara  Minoru Kataoka  Hiroshi Kubota 《Compost science & utilization》2013,21(4):47-51

The effect of Bacillus licheniformis HA1 cell density on the acceleration of organic waste composting was tested in a bench-scale composting system utilizing a process limit temperature of 60°C. Variables measured during composting were CO₂ evolution rate, conversion of substrate carbon and pH. When an initial cell density of 2.0×10⁴ cfu/g-dry solid was used, the strain HA1 increased in number and prevented the decrease in pH during the early stage of composting. This resulted in enhanced populations of other thermophiles and increased the rate of organic matter decomposition. By contrast, no effect was observed at a lower cell density of HA1. It was found that the minimum cell density of HA1 to accelerate organic decomposition was around 10⁴-10⁵ cfu/g dry solid of raw material.  相似文献   

An index for evaluating the flood-prevention function of paddies     

Takao Masumoto  Takeo Yoshida  Tomijiro Kubota 《Paddy and Water Environment》2006,4(4):205-210

Urbanization is expanding in and around small to medium-sized cities as well as in large cities, and the expansion includes low-lying areas where the flood risk is high. Flood risk in small watersheds has been evaluated using precise mathematical models. However, these models cannot be applied to larger basins due to the complexity of data collection and analysis. As a result, quantitative evaluations of flood risk at macro scales and the flood-prevention function of paddies around urban areas have not been made. This paper proposes a method and an index that can be used to evaluate the flood-prevention function of paddies on a regional scale. In addition, the use of this system for basin-wide management is illustrated by an example for the Kinu and Kokai rivers, which are tributaries of the Tone River of Japan. The applicability of the approach is evaluated using data from a major flood that occurred in the study area.  相似文献   

Amphidinolide C2, New Macrolide from Marine Dinoflagellate Amphidinium Species     

Takaaki Kubota  Yusuke Sakuma  Masashi Tsuda  Jun’ichi Kobayashi 《Marine drugs》2004,2(3):83-87

A new cytotoxic 25-membered macrolide, amphidinolide C2 (1), has been isolated from marine dinoflagellate Amphidinium sp. (Y-71 strain), and the structure 1 was elucidated on the basis of spectroscopic data and chemical means.  相似文献   

Ground-dwelling beetle community in beech forests of Sado Island,Japan: comparison with the mainland     

Hiroshi Ikeda  Kosuke Homma  Kohei Kubota 《Journal of Forest Research》2008,13(6):357-364

Island ecosystems differ from mainland ecosystems in their long-term isolation. On Sado Island, Japan, cattle grazing in the past gradually changed forests into grasslands, thereby altering the diversity of indigenous insects. We compared ground-dwelling beetle diversity on Sado Island to that on the nearby mainland. Contrary to previous reports, the island isolation effect resulted in lower γ and β diversity than on the mainland, because of the low species richness of beetles with low dispersal abilities. Few flightless beetles could invade Sado Island, even when the beech forests on the island were relatively adjacent to those on the mainland. Such a history of ecosystem formation could be the general pattern for continental-island mountain forests that were never connected to those of the mainland. We did not observe low α diversity of ground-dwelling beetles, suggesting that the cattle grazing history of the island has not changed environmental conditions for ground-dwelling beetles enough to reduce their diversity. In addition, cattle grazing increases the abundance of merdivorous insects by increasing the abundance of their food resource. Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users.  相似文献   

A new spore precipitator with polarized dielectric insulators for physical control of tomato powdery mildew     

Matsuda Y  Ikeda H  Moriura N  Tanaka N  Shimizu K  Oichi W  Nonomura T  Kakutani K  Kusakari S  Higashi K  Toyoda H 《Phytopathology》2006,96(9):967-974

ABSTRACT In an attempt to physically protect greenhouse tomato plants from the powdery mildew fungus Oidium neolycopersici, we developed a new electrostatic spore precipitator in which a copper wire conductor is linked to an electrostatic generator and covered with a transparent acrylic cylinder (insulator). The conductor was negatively charged by the generator, and the electrostatic field created by the conductor was used to dielectrically polarize the insulator cylinder. The dielectrically polarized cylinder also produced an electrostatic force without a spark discharge. This force was directly proportional to the potential applied to the conductor and was used to attract conidia of the pathogen. The efficacy of this spore precipitator in protecting hydroponically cultured tomato plants from powdery mildew was evaluated in the greenhouse. The hydroponic culture troughs were covered with a cubic frame installed with the spore precipitator, and the disease progress on precipitator-guarded and unguarded seedlings was traced after the conidia were disseminated mechanically from inoculum on tomato plants. Seedlings in the guarded troughs remained uninfected during the entire experiment, in spite of rapid spread of the disease to all leaves of the unguarded seedlings.  相似文献   

Marigold Leaf Spot Caused by Alternaria tagetica New to Japan     

Keisuke TOMIOKA  Toyozo SATO  Hiroki KOGANEZAWA 《Journal of General Plant Pathology》2000,66(4):294-298

In October 1998, a disease causing mainly foliar necrotic lesions was found on African marigold (Tagetes erecta) and French marigold (T. patula) grown in Miyagi Prefecture, Japan. Similar lesions also developed on stems and flowers, resulting in early blight of the affected organs. Plants with numerous lesions withered rapidly. A mitosporic fungus isolated repeatedly from the diseased plants was identified as Alternaria tagetica and demonstrated to cause the disease. The disease, as well as the fungus, is new to Japan. We propose the name “hanten-by?”, which means leaf spot in Japanese, for this disease. Received 5 April 2000/ Accepted in revised form 31 May 2000  相似文献   

Induction of gelatinolytic activities in ayu muscle at the spawning stage   总被引：1，自引：0，他引：1  

Satoshi Kubota  Masato Kinoshita  Yoshihiro Yokoyama  Haruhiko Toyohara  Morihiko Sakaguchi 《Fisheries Science》2000,66(3):574-578

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Middle upper beak fracture in a Red-crowned crane that completely recovered with external skeletal fixation     

Hiroko IIMA  Hiroki TERAOKA 《The Journal of veterinary medical science / the Japanese Society of Veterinary Science》2021,83(4):742

An adult Red-crowned crane in captivity that had a displaced compound fracture of the middle upper beak caused by an accident was treated by using Type I-a external skeletal fixator (ESF). The ESF that was equipped with a unilateral epoxy putty fixator and with five half-pins was fixed on the premaxilla bone. The crane with the ESF on the beak was able to feed smoothly by itself. The ESF was removed 49 days after the first surgery. Beak malocclusion, which was observed in the latter half period of fixing, spontaneously improved within one month after removal of the ESF. This is the first successful case of repair of an upper beak fracture in a Red-crowned crane.  相似文献   

Heterogeneity in immunologic functions among canine alveolar macrophage subfractions     

Y Oghiso  Y Kubota 《Nippon juigaku zasshi. The Japanese journal of veterinary science》1986,48(6):1125-1134

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